program oken; uses crt; var i,n:longint; s: real; begin clrscr; write('nhap n: '); readln(n); for i:=1 to n do s:=s+ 1/(i*(i+2)); writeln('Tong S: ',s:0:3); readln; end.
cách 2( dùng while-do):
program oken; uses crt; var i,n:longint; s: real; begin clrscr; write('nhap n: '); readln(n); i:=1; s:=0; while i<=n do begin s:=s+ 1/(i*(i+2)); i:=i+1; end; writeln('Tong S: ',s:0:3); readln; end.
var i,n:longint; s: real; begin clrscr; write('nhap n: '); readln(n); for i:=1 to n do s:=s+ 1/(i*(i+2)); writeln('Tong S: ',s:0:3); readln; end.
`text{C2:}`
program oken; uses crt;
var i,n:longint; s: real; begin clrscr; write('nhap n: '); readln(n); i:=1; s:=0; while i<=n do begin s:=s+ 1/(i*(i+2)); i:=i+1; end; writeln('Tong S: ',s:0:3); readln; end.
